Initial commit

README.md

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+A simple pub-sub threaded cv webcam opener

cv_webcam_pub.py

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+import pubsub
+import queue
+import cv2
+import numpy as np
+import threading
+
+if False:  # don't include if actually running
+    from typing import List, Union, Tuple, Any, Callable
+
+
+def get_open_cv_cam_ids():  # type: () -> List[cv2.VideoCapture]
+    cam_list = []  # type: List[int]
+
+    while True:
+        cam = cv2.VideoCapture(len(cam_list))
+        if not cam.isOpened():
+            break
+        cam_list.append(len(cam_list))
+
+    return cam_list
+
+def pub_cv_cam_thread(camId # type: Union[int, str]
+                      ):
+    sub = pubsub.subscribe("cvcams."+str(camId)+".cmd")
+    msg = ''
+    cam = cv2.VideoCapture(camId)
+    if not cam.isOpened():
+        pubsub.publish("cvcams." + str(camId) + ".status", "failed")
+        return False
+    while (  msg != 'q'):
+        (ret, frame) = cam.read()  # type: Tuple[bool, np.ndarray ]
+        if ret is False or not isinstance(frame, np.ndarray):
+            cam.release()
+            pubsub.publish("cvcams." + str(camId) + ".status", "failed")
+            return False
+        pubsub.publish("cvcams."+str(camId)+".vid", (frame,))
+        msg = listenFixed(sub, block=False, empty='')
+
+        pass
+    cam.release()
+    return True
+
+def listenFixed(sub, block=True, timeout=None, empty=None):
+    try:
+        msg = (sub.listen(block=block, timeout=timeout))
+        try:
+            msg = next(msg)['data']
+        except StopIteration:
+            msg = empty
+    except queue.Empty:
+        msg = empty
+    return msg
+
+
+def init_cv_cam_pub_thread(camId # type: Union[int, str]
+                      ):
+    # type: (...) -> threading.Thread
+    t = threading.Thread(target=pub_cv_cam_thread, args = (camId,))
+    t.start()
+    return t
+
+def cv_cam_pub_handler(camId, # type: Union[int, str]
+                       frameHandler # type: Callable[[int, np.ndarray], Any]
+                       ):
+    t = init_cv_cam_pub_thread(camId)
+    subCam = pubsub.subscribe("cvcams."+str(camId)+".vid")
+    subOwner = pubsub.subscribe("cvcamhandlers."+str(camId)+".cmd")
+    msgOwner = ''
+    while msgOwner != 'q':
+        frame = listenFixed(subCam, timeout=.1)  # type: np.ndarray
+        if frame is not None:
+            frame = frame[0]
+            frameHandler(frame, camId)
+        msgOwner = listenFixed(subOwner, block=False, empty='')
+    pubsub.publish("cvcams.0.cmd", 'q')
+    t.join()
+
+def init_cv_cam_pub_handler(camId, # type: Union[int, str]
+                            frameHandler # type: Callable[[int, np.ndarray], Any]
+                      ):
+    # type: (...) -> threading.Thread
+    t = threading.Thread(target=pub_cv_cam_thread, args = (camId, frameHandler))
+    t.start()
+    return t
+
+if __name__ == '__main__':
+    i = 0
+    def testFrameHandler(frame, camId):
+        global i
+        if i == 200:
+            pubsub.publish("cvcamhandlers."+str(camId)+".cmd", 'q')
+        if i % 100 == 0:
+            print(frame.shape)
+        i += 1
+
+    cv_cam_pub_handler(0, testFrameHandler)
+

get_webcams.py

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+import numpy as np
+import cv2
+
+#todo: add dshow, v4l
+
+if False:  # don't include if actually running
+    from typing import List, Tuple
+
+
+def make_camlist():  # type: () -> List[cv2.VideoCapture]
+    cam_list = []  # type: List[cv2.VideoCapture]
+
+    while len(cam_list) == 0 or cam_list[-1].isOpened():
+        cam_list.append(cv2.VideoCapture(len(cam_list)))
+
+    return cam_list
+
+def capture_cams(cam_list  # type: List[cv2.VideoCapture]
+                 ):  # type: (...) -> List[np.ndarray]
+    frame_list = []
+    for c in range(len(cam_list)):
+        (ret, frame) = cam_list[c].read()  # type: Tuple[bool, np.ndarray ]
+        if ret is False or not isinstance(frame, np.ndarray):
+            cam_list[c].release()
+            cam_list.pop(c)
+            continue
+        frame_list.append(frame)
+    #        for i in range(100):
+    #                    try:
+    #                        print(i, cam_list[c].get(i))
+    #                    except:
+    #                        break
+    #        exit()
+    return frame_list
+
+
+def show_cams(cam_list  # type: List[cv2.VideoCapture]
+              ):  # type: (...) -> None
+    while True:
+        frame_list = capture_cams(cam_list)
+        for f in range(len(frame_list)):
+            print(frame_list[f].shape)
+            cv2.imshow('frame' + str(f), frame_list[f])
+        if cv2.waitKey(1) & 0xFF == ord('q'):
+            break
+
+
+def end_cams(cam_list  # type: List[cv2.VideoCapture]
+             ):  # type: (...) -> None
+    for cam in cam_list:
+        cam.release()
+

requirements.txt

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+opencv-python
+pubsub
+numpy